Zinc(II), copper(II) and nickel(II) ions improve the selectivity of tetra-cationic platinum(II) porphyrins in photodynamic therapy and stimulate antioxidant defenses in the metastatic melanoma lineage (A375)

Abstract

Tetra-cationic porphyrins with peripheral Pt (II) -bipyridyl complexes demonstrated a potential as photosensitizers to be used in photodynamic therapy (PDT). First-line transition metals, such as zinc (II), copper (II) and nickel (II), can be incorporated into the porphyrin nucleus, making this molecule more selective and more effective for this therapy in combating to tumor cells, such as metastatic melanoma. We characterized these derivatives to verify the improvement in selectivity of platinum (II) 4-PtTPyP porphyrins. Receptors such as LDL and endothelin (ERT-B) were investigated, as well as the binding affinity of two antioxidants: catalase model enzymes and superoxide dismutase. Human serum albumin (SAH) HSA binding properties have been verified. In addition, we evaluated the antitumor action of such metalloporphyrins in an in vitro cell viability. Our results demonstrated that porphyrins have significant antitumor potential when exposed to white light conditions. The affinity for the LDL receptor was better when compared to platinum porphyrin 4-PtTPyP without addition of metals and the affinity for the endothelin receptor was higher than the control used in this study. Still, the interaction with the HSA showed the possibility of this connection taking photosensitizers to places of interest, such as the delivery of medicines.

Keywords: Cancer; Endothelin receptor (ERT-B); LDL receptor; Metalloporphyrins; Photodynamic Therapy.